Journal of Agricultural Sciences and Natural Resources
Year:2005 | Volume:12 | Issue:SUPPLEMENT (SPECIAL ISSUE ANIMAL SCIENCE)|Papers Count:24

Considering importance of trace element in animals food, recognizing the circumstances of mineral elements seems to be necessary particularly in desert regions in Iran and as a consequence Semnan province Mineral elements such as selenium (Se) can be used and acted as a limiting factor in animal products in different seasons of year in Semnan province. For selenium concentration determining, ten cattles of sheep and goats were selected by systematic random sampling and each cattle of sheep and goats were divided in to three age categories, Le (0-1), (1-3) and 3 years and over, with 10 observations in four seasons Furthermore, blood samples were taken and after separating blood serums. Se concentration was measured through Neutron Activation Analysis (N.A.A). Se concentration of blood serum has scientific meanings, therefore the maximum counting observed in the winter and minimum counting in the spring season (104.646 ppb and, 79.688 ppb). The effect of sex on selenium concentration was significant (P<0.05), therefore the concentration Se in the females were more than the males (94.148 ppb and, 86. 718 ppb). The effect of the age has also significant (P<0.05) (100.553 ppb, and 76.323 ppb). The concentration of the blood Se has also increased, but there were not any significant different between sheep and goats. The responsiveness between age, sex and species factors have no significant meanings.  

Test dat milk and fat yield records from first calving Holsteins were analyzed using single trait random regression test day model (RR/CF model) and restricted maximum likelihood method. Fixed random regressions (additive genetic and permanent environmental) were modeled with orthogonal legendre polynomials on days in milk. Residual variance components during lactation were estimated using 3th order variance function. According to the results, for milk yield trait a random regression model with 3 and 4 orders of fit for additive genetic and permanent environmental covariance functions, respectively and for fat yield trait 3 order of fit for both covariance functions are suitable. Phenotypic variance during lactation was not constant and was higher at the beginning and the end of lactation. Maximum residual variance for milk and fat yield traits was estimated in early lactation. Minimum and maximum additive genetoc variance for both traits was estimated at the beginning and 8th month of lactation, respectively. Estimates of heritability were found to be lowest during early lactation. This parameter increased to mid lactation and maximized nearly in the 8thmonth of lactation (0.28 for milk yield and 0.22 for fat yield). Additive genetic and permanent environmental correlations between adjacent test days were more than between distant test days.  

In order to investigate the nutritional effects of mulberry varieties (Morus sp) on economical, biological and biochemical characters of silkworm Bombyx mori, hybrid 103×l 04 larvae were reared on two varieties of mulberry, Le. Isfahan local variety and Kokoso. Data showed that larval performance i.e., larval weight, the percentage of daily increase of weight and larval duration were considerably improved by kokoso variety. Also cocoon parameters like cocoon weight, pupal weight and cocoon shell weight were increased in this group in comparison with larvae which fed on local mulberry leaves. The amounts of glucose and urea in heamolymph of 5th instar larva feeding on kokoso variety were much more than the other group. The increase of urea in larval heamolymph indicates that catabolic reactions of proteins and amino acids were activated and increased in this group. Also this amount of urea was reabsorbed by silk gland for silk protein synthesis and it causes increase in cocoon production of this group. But the amounts of triacyleglyceroles, cholesterol and minerals like calcium, phosphorus and ferrous in the larva which were fed by local mulberry leaves were more than others. This data indicates that metabolic activity in this group is lower and causes accumulation of these compounds in heamolymph.  

With analyzing test day milk records of first lactation Holsteins using random regression models, the effect of assuming a constant residual variance during lactation on the other (co)variance components and heritability of milk yield was studied. Additive genetic and permanent environmental covariance functions were estimated using 3rdorder orthogonal Legendre polynomial and different assumptions of residual variance in the analysis including the assumption of constant (homogenous) and variable (heterogeneous) residual variance during lactation were investigated. According to the results, the assumption of variable residual variance during lactation resulted in significant increase (P<0.05) in the log-likelihood and improved the fitness of derived covariance functions. Maximum residual variance of milk yield was in early lactation, then declined to mid lactation rapidly and finally increased a little in late lactation. Assuming a constant residual variance during lactation, residual variance was underestimated and heritability was overestimated nearly in mid lactation. Because the number of estimated parameters increases with the assumption of variable residual variance, using of a variance function for different estimates of mentioned component for each day or stage of lactation was recognized as suitable.  

Investigation on Semirum range forage from mineral status point of view have been shown that phosphorus, magnesium and copper content of these forages were deficient. Therefore the consumption of mineral supplement is essential. The aim of this experiment was evaluation effects of mineral supplement on growth and body weight of lambs in range of Semirum. Sixty-six native lambs from Semirum area were used for this trial during months of June and Oct. of 2000 (grazing season). All lambs were adapted for 14 days on range at Hamzavi Research Station. Then the lambs were allocated to 3 treatment groups on the live weight basis. Control group had an average live weight of 26.44±3.84Kg with no access to mineral blocks. Second group with an average live weight of 26.45±3.76Kg with access to common mineral block (CMB). Third group with an average live weight of 26.43 ±3.80 Kg with access to special mineral block (SMB), which provides deficient mineral in Semirum range forages. All lambs were grazed on the range from morning until evening and then they were housed in individual pen for night. All groups had ad libitum access to water and mineral supplement for only group 2 and 3. Lambs body weights were taken monthly. The intake of mineral blocks had significant effect on the body weight and growth rate of lambs in last month of grazing period (P< 0.05). Daily gain and live weight gain of lambs in treatment group of 2 and 3 were significantly higher than control (p< 0.01). However daily live weight gain 5MB group were higher than CMB group but there were no significant difference between them.  

In this experiment effects of diets containing different levels (0, 3, 6 and 9%) of silkworm pupae meal (SWPM) on the performance of male broiler chicks using 13 feeding treatments in a completely randomized design were evaluated. Seven hundred and eighty day-old male broiler chicks (Arain) were randomly divided into 52 groups of 15 chicks each. Four replicates were assigned to each treatment, randomly. The experiment lasted for 49 days. The results showed that different levels of SWPM had no significant effects on daily feed intake and weight gain during 0-42 d period. In total experimental period (0-49 d of age) daily feed intake and weight gain considerably were higher in groups fed diets containing silkworm pupae meal compared with chicks fed diets containing fish meal as a main source of animal protein. None of the feeding methods caused significant effect on feed conversion ratio in 0-42 and 0-49 days of age. However, total chicks fed diets containing different levels of SWPM during rearing period had a higher body weight mean than control group at 49 days of age (2136 g vs. 2046 g). Moreover, the treatments had no significant effects on relative percentage of carcass, abdominal fat and pancreas to live body weight at 49d of age. According to the results of this experiment we can include SWPM in broiler chick diets as a main source of animal protein, without having any adverse effects on their performance.  

Forty Shall breed of 2-4 years old ewes were selected in Research Centre of Faculty of Veterinary, University of Tehran. In spring, estrus synchronization of ewes were carried out using CIDR containing progestrone hormone for a period of 12 days with an  intramuscular1yinjection of PMSG after its removal from vagina. Semen samples was collected from five Shall breed of rams using an artificial vagina. Suitable semen samples were pooled and diluted with sterilized and homogenized cow milk at 30°c. Straws were filled with 0.2 ml of diluted semen and stored at 18°cfor 4 hours until use. Concentration of diluted semen was measured by haemocytometry method. Estrus synchronized ewes detected by a teasere ram and divided into two groups for cervical and uterine insemination. After 50 hours of PMSG injection, artificial insemination was carried out by placing a vaginoscope into vagina, fixing the cervix by a forceps, forcing a bented-tip pipette, specially designed to pass the cervical folds through cervical lumen. Pipette was pushed forward by gentle rotation as far as possible and semen was injected either in cervical folds or in uterine body. Non-return and pregnancy rates of ewes were measured after 16-17 and 30 days of artificial insemination. All ewes were synchronized and non-return rates of inseminated ewas were 100%. Mean pregnancy rate of inseminated ewes was 47.5%, for young and aged ewes 52 and 43% respectively. Mean pregnancy percentages of ewes inseminated cervical were 42.5 and 52.5 for uterine insemination. The Results showed that effect of place of injection of semen on ewes pregnancy rates was not significant (P>0.05).  

In order to determine bitter vetch and vetch and alfalfa digestibility via in vivo and in vitro method, an experiment was conducted with 16 Ghezele wethers. In this experiment the digestibility was determined through regression equations correlation coefficient was calculated between in vivo and in vitro methods. The chemical analysis of alfalfa and bitter vetch were determined. In in vivo method, four trents containing 0, 25, 50 and 75 percent of bitter vetch were considered with alfalfa based diet, In this method, digestibility of all nutrients except crude fiber and ADP were increased significantly with increased bitter vetch leaves but a significant difference was not observed between crude protein digestibilities in rations containing 50 and 75% of bitter vetch. Relationship between bitter vetch levels and all of digestible nutrients waslinear and its r2 was 98%. In the method of in vitro, dry matter, organic matter and organic matter per dry matter of ration were increased with increasing of bitter vetch ratio from zero to 100%but there was not any significant difference between organic matter and organic matter per dry matter between zero and 25% of bitter vetch levels. The correlation coefficients between results of in vivo and in vitro methods on dry matter, organic matter and D-value for alfalfa were 99, 99 and 97 and bitter vetch was 97, 98 and 96 respectively. Among treatments, feed containing 50% alfalfa and 50% bitter vetch had the highest voluntake, but metabolizable energy from intake containing 25% alfalfa and 75% bitter vetch was the highest. It is worth mentioning that concentration of metabolizable energy increased with increasing of bitter vetch ratio.  

In this study 4136 records of ewe Clean fleece weight and 3135 records of litter size collected during the period 1990-2000 from a flock at Rearing and Breeding of Lori-Bakhtiari sheep Station in Shahre-Kord were used to estimate (Co)variance components and genetic parameters of ewe Clean fleece weight and litter size. (Co)Variance components and genetic parameters were estimated using Derivative Free Restricted Maximum Likelihood (DFREML) with univariate and bivariate animal models including fixed effects of year, ewe age and regression coefficient of ewe body weight, and random effects of additive genotype of ewe, permanent environment and residuals. Least-squares means (±s.e.) of ewe Clean fleece weight and litter size were 1.95±0.01kg and 1.16±0.006 head, respectively. Effects of year and ewe age on traits under study were highly significant (p<0.001). Estimation of variance components from univariate were the same as bivariate analysis. Estimation of genetic (co) variance components were 0.108±0.011 and 0.016±0.005 for ewe Clean fleece weight and litter size and - 0.002±0.005 for genetic covariance between them. Estimation of genetic parameters for ewe Clean fleece weight and litter size were respectively 0.56±0.04 and 0.13±0.04 for heritability, 0.64 and 0.28 for repeatability and - 0.04±0.04 for genetic correlation between two traits. The results of this study showed that the rate of response to selection for litter size will be slow, while selection for ewe Clean fleece weight resulting considerable progress for this trait without any negative effect on litter size.  

This experiment was carried out based on 5913 records of Baluchi sheep from Abas Abad Animal Breeding Station in North East of Iran. The under study traits were, birth weight, three months, six months, nine months and yearling weights. Six different models of DFREML software were used. Genetic parameters were estimated by REML method with the animal model. Age of dam, sex of animal, birth type, year and month of birth was regarded as fixed factors in analysis data and traits. Number of days between birthday and time of obtaining each trait were used as a covariate for correcting the real data. The estimated heritability for birth weight, three, six, nine and twelve (yearling) months were 0.14 (0.033), 0.28 (0.045), 0.25 (0.05), 0.28 (0.052) and 0.33 (0.055) respectively. It was conduced that increasing the age of animal, direct genetic effects on weight traits also increased significantly.  

This Experiment was conducted to investigate the impacts of different levels of the hull-less barley on broilers performance and their gut activity. Nine hundred and sixty one days old Arbor Acres broiler chicks were used in a 4x3 factorial arrangement with 4 levels of hull-less barley (0, 10,20 and 30%) and 3 levels enzyme (0, 300 and 600g/ton). Four replicates were allocated to each treatment. Increasing in hull-less barley inclusion rate to diet increased dietary concentration of soluble NSPs. In starter and grower periods, different levels of hull-less barley had significant effects on feed intake, weight gain and feed conversion ratio (P<.0.01). In finisher period, different levels of hull-less barley had no significant effects on performance variables. At the overal rearing period (0-49 days), increasing in hull-less barley to diet, affected significantly weight gain, feed intake and feed conversion ratio (p<0.01). Increasing in hull-less barley levels in diet increased the weight of gastrountestinal track, liver and ceca relative to whole body (P<.0.01) but the abdominal fat and gizzard weight and mortality weren't affected by these components. Addition enzyme to diets had no significant effects on studied variable. The results of this experiment suggested that hull-less barley can be include in broiler diets to the extent that soluble NSPs in diet don't go upper than 3.6, 4.1 and 4.6 % in starter, grower and fisher periods, respectively. However, considering diet composition, it suggests to use hull-less barley 0, 20 and 30% in starter, grower and finisher diets, respectively.  

This study was conducted to: I) investigate the relationships between serum urea nitrogen concentrations (SUN) and serum steroid hormones concentrations and 2) relate SUN to pregnancy in dairy cows. Blood samples were collected at the day of insemination from 75 lactating cows of a dairy farm, which came into heat during a 4 weeks period. Forty-Five days after insemination, cows were determined to be either pregnant or non-pregnant. Average SUN concentrations of non-pregnant cows were significantly higher than those of pregnant cows (p<0.05). There were no significant differences between mean estradiol and progesterone concentrations of pregnant and non-pregnant cows. Also, based on SUN mean (15 mg/dl), cows were divided into two groups: 1- cows with SUN concentrations less than mean and 2- cows with SUN concentrations greater than mean. Progesterone concentrations between these groups were not significantly different. However, mean estradiol concentration of group 1 was significantly greater than those of group 2 (p<0.05). There was a significant correlation between SUN and estradiol concentrations (r=-0.43, p<0.05). The progesterone concentrations tended to increase (r= -0.23, p=0.06) as SUN concentrations increased. The observed negative effects of urea on fertility in this study may be mediated by effect on steroid concentration.  

Milk production and composition of 2-3 years old ewes from two Iranian breeds (Shall, n=20; and Zandi, n=19), giving birth of single lambs were studied. Average lactation length and milk yield were 119 days and 110.3 kg for shall, and 91 days and 40.95 kg for Zandi ewes. Ewe age (2 and 3 years) had not a significant effect on total milk production. The ewes suckling ram lambs produced more milk (114.3±1.96kg for shall and 43.4±1.80kg for Zandy) compared with those suckling ewe lambs (106.3±1.60kg for shall and 38.2±1.11 kg for Zandy) (P<0.05). Average daily gain and total weight gain were greater for the ram lambs than for the ewe lambs and the difference in shall was significant (P<0.01). The weaning weight of ram lambs in both breeds were higher than ewe lambs (P<0.01). The mean fat content of the milk was 5.85 and 6.080%, the mean protein content was 5.50 and 5.45%, the mean lactose content was 5.03 and 4.52% and the mean non-fat solids content was 11.77 and 11.55% in Shall and Zandi ewes respectively.  

This Study was conducted to evaluate the effects of different levels of Sulfur containing amino acids (80 to 120 Percent of requirements) content of diet on young breeders growth and adult breeders performance in three stages. Management and diets were as descried by Arian company. The experimental diets were isocaloric but contained various levels of Methionine. The experimental design was completely randomized design (CRD). The results of this experiment indicate that young breeders growth was not significantly affected due to sulfur amino acids levels (P>0.05). Also EP (%), EM (g/hen/day), Hatchability (%) and day old off spring body weight (g) were not influenced by sulfur amino acid levels (P<0.05). Under the condition of this experiment, diet containing 80 percent of sulfur containing amino acids requirements with 17 percent of crude protein seems to be enough to support an acceptable performance for both young and adult Arian broiler breeders.  

Two groups of silkworm (Bombyx mori-L) contain China (32, 104 and 110) and Iranian native silkworms (Guilan orange, Khorasan orange, Khorasan lemon, Khorasan pink and Bagdadi) were genetically compared. In this comparison ISSR markers were used with three primers. DNA was extracted from sericigene glands by modified Suzuki method (phenol-chloroform method). A set of three 5'-anchored repeat primers amplified a total of253 bands out of which %100 were polymorphic. Effective number of alleles average for total populations were 1.518 and genetic diversity average was 0.3194. A dendrogram was constructed using the UPGMA method. Maximum polymorphism was seen in 110 and minimum in lemon. Maximum unbiased genetic distance was between Gilani and 104 and minimum was between 110 and Baghdadi that were in one group. These results show that this marker is probably a useful tool for recognizing species, races, insect's biotype and phylogenetic studies.  

An experiment was conducted in completely randomized design (CRD) with 6 dietary treatments and 4 replicates each with ten hens from 94 to 106 wk of age. Three 28-d periods used from different dietary factors including: l)Control (C); 2)Low Methionine (LM); 3)Low Linoleic Acid (LLA); 4)High Energy (HE); 5) Low Methionine, Linoleic Acid, Choline and High Energy (LM-LLA-LCH-HE) and 6)Low Choline (LCH). Overall feed intake was significantly (P<0.05) lower for the hens fed HE diets compared to the control. Overall egg weight was significantly (P<0.05) lower for the hens fed LM and LM-LLA-LCH-HE compared to the control. Liver hemorrhage score (LHS) was positively correlated (P<0.05) with liver weight. Serum enzyme activities including: aspartate amino teransferase (AST), alanine amino teransferase (ALT), lactate dehydrogenase (LDH) were not significantly affected by dietary treatments. Although the AST enzyme activity was not significantly different, it was numerically higher for all dietary treatments except HE diet. The results showed the effectiveness of dietary factors on induction of FLHS in laying hens. AST enzyme activity could be used for diagnosis of FLHS in laying hens.    

In order to investigate the compensatory growth, comparison of carcass characteristics and feed intake in Atabay lambs, an experiment was conducted using 21 male lambs. Lambs of 5-6 months with the average of 35±5kg were divided to finishing treatments (first treatment), 30 (2nd treatment) and 60 days restriction groups (3rdtreatment). At the end of the experiment 4 lambs from each treatment were slaughtered for carcass analysis. The differences in characteristics of skin, head and leg, neck, flank+brisket, shoulder, chest and ribs, feet, back, hot carcass, cold carcass, bone carcass, hearts, kidney, lung, liver and fat-taile weights between the treatments was significant (p< 0.05). The result showed no significant differences in characteristics including full and empty gastrointestinal tract, tallow, back bone fat depth, fat carcass, back muscle carcass section and carcass length (p> 0.05). Feed conversion coefficient restricted treatments after the period of restriction compared with control treatment was decreased (2ndtreatment 12.18 and 5.98 - 3rdtreatment 4.08). Daily gain increasing between the treatments in the end period was not significant (p>0.05). Therefore, the 30 days restriction treatment was preferred for optimum feeding, saving in feed consumption and carcass with less fatness.  

The effect of dietary supplemental ascorbic acid (AA) and nutrient density on the male broilers' response exposed to heat stress, a diurnally cyclic temperature (24-38-24 ºC), was investigated in this study. A 3×6 factorial arrangement in a completely randomized block design was used. Factors involved in the experiment were three levels of dietary supplemental ascorbic acid (0, 200 and 400 ppm) and six kinds of diet with different nutrient density (I-very low energy-medium protein diet, 2-low energy-medium protein diet, 3-medium energy-medium protein diet without fat, 4-medium energy-medium protein diet with fat, 5-medium energy-high protein diet, and 6-high energy-high protein diet). Each treatment was tested with three replicate cages of 9 birds. Experimental period was from 2 to 8 weeks of age. The effects of ascorbic acid and diets on body weight gains (BWG), feed conversion (FC), feed intake (FI) and carcass quality (including: relative weights of carcass, visceral, abdominal fat pad and gall bladder and liver) were investigated. The results could not indicate any significant differences in BWG, FC and FI between different levels of AA. However, there were significant differences between the diets (P<0.05). The highest and the lowest BWG were related to High Energy- High protein and Very Low Energy-Medium protein diets, respectively. The effect of various levels of AA on the carcass quality was significant only for abdominal fat pad percentage (p<0.05). Abdominal fat pad percentage showed a decreasing trend with increasing the levels of AA in the diets. The diets had significant effects on most carcass quality traits (P<0.05). As a consequence, the results of this study indicated that some increase in nutrient density of the diet can lead to a reduction in the adverse effects of heat stress on the performance of male broilers exposed to hest stress. The improvement in BWG achieved by the chicks fed Medium Energy-Medium Protein with Fat diet, compared to those fed Medium Energy-Medium Protein without Fat diet, confirms the findings of other workers in relation to the beneficial effects of dietary fat on the performance of broilers exposed to heat stress.